CSS-Tricks #15 Introduction to Firebug

Firebug is an essential Firefox extension for web designers and developers. You are able to quickly target any element on a page to see the markup, the CSS, the layout, and the DOM in an instant. Not only can you see all of this juicy information, you can edit and see the results directly in the browser window. This makes Firebug the go-to tool for debugging CSS trouble. Also indispensable for JavaScript programmers.